A cab is, fundamentally, a post-amp EQ. Mic'ing further adds tailoring to said EQ, and the cab / mic'ing part is as important if not more to the sound as a whole as the amp itself, so it is only natural the impulse that results from said process will have a part to play. A simple test of how dramatic things get is to just play with different mics with one cab on whatever modeler you wish and then to simply swap cabs around. When we go for high gain tones, it's super noticeable how much of the overall tone shaping is happening at the cab block since many of the subtleties of certain preamps being mitigated by the compression caused by heavier distortion. In other news, FX spillover is now in beta stage and I'll be testing that today. I'll let you know how that one goes.